1. Field of the Invention
The present invention relates to a lateral resonant tunneling transistor having two non-symmetric quantum dots. In particular, the both of the ends of 2-dimensional electron gas (which is generated in a hetero-join structure of a compound semiconductor material) are provided respectively with terminals, and a plurality of split gates are formed in parallel above a channel through which the two dimensional electron gas passes.
2. Description of the Prior Art
The conventional transistors having the split gates are described in "Springer series in Electronics and Photonics" vol. 31, p 159-167, and in "Coulomb-Blockade Oscillations in Quantum Wires and Dots".
The above mentioned conventional transistor is constituted such that a plurality of split gates are arranged in a radiative form around a central point. Thus by providing a plurality of split gates and by supplying a negative voltage to the gates, a quantum dot is formed at the central point.
The current which is adjusted in the above described manner owes mainly to a resonant tunneling effect. That is, when the energy levels of the electrons of the opposite sides across a potential barrier correspond with each other, the electrons moves through the potential barrier.
For example, the resonant tunneling of electrons occurs in the following manner. That is, in the case where the region capable of accommodating electrons is divided into two portions across an electric potential barrier, when the energy levels of the electrons of the respective portions correspond with each other, the electrons of the energy level of one side moves through the electric potential barrier to the vacant energy level of the other side.
In such a resonant tunneling, the transmittance of the resonant tunneling depends on the height and thickness of the electric potential barrier.
The resonant tunneling phenomenon represents the negative differential resistance in the current-voltage characteristics.
In the conventional device utilizing the resonant tunneling phenomenon, there is the disadvantage that the adjustment of the current is difficult. The reason is that the adjustments of the quantum dots are difficult. Further, diversified current-voltage operation characteristics are difficult to obtain, with the result that the application range is very narrow.